<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>图像与动画</title>
  </head>
  <body>
    <video src="./录屏.mp4" controls width="400" height="400" muted></video>
    <script>
      const canvas = document.createElement("canvas");
      canvas.width = 400;
      canvas.height = 400;
      document.body.append(canvas);

      const ctx = canvas.getContext("2d");

      const video = document.querySelector("video");
      video.addEventListener("play", function () {
        draw();
      });

      ctx.arc(200, 200, 150, 0, Math.PI * 2);

      function draw() {
        ctx.clearRect(0, 0, 400, 400);
        ctx.drawImage(video, 0, 0, 400, 400);
        requestAnimationFrame(draw);
      }
    </script>
  </body>
</html>
